Moving body track indicator system

ABSTRACT

A moving body track indicating system for displaying the track of a moving body along with latitude and longitude line markers and cursors on an indicating device such as a cathode-ray tube. The displayed pattern can be automatically magnified or reduced and shifted to a desired position. Cursor markers are displayed parallel to the latitude and longitude line markers with identifying symbols displayed along with the cursor markers. A reference point is automatically readjusted wherein the moving body, a ship in the preferred embodiment, moves beyond the edge of the display surface.

.Iadd.This is a continuation of application Ser. No. 600,269, filed Apr.12, 1984 now abandoned which is a reissue of U.S. Pat. No. 4,400,780..Iaddend.

BACKGROUND OF THE INVENTION

The present invention relates to a moving body track indicating systemfor indicating on the display surface of an indicator longitude andlatitude line markers as well as the track of a moving body.

A moving body track indicating system typically includes a navigationaid apparatus as a Loran receiver, an Omega receiver or an NNSS (NavyNavigation Satellite System) receiver for measuring the positions ofmoving bodies. Such systems utilize the output signals from the receiverto successively plot the positions of the moving body in which thesystem is utilized on an indication medium such as a recording paper onwhich longitude and latitude line markers have been previously printedthereby indicating the track of the moving body thereon. Such a movingbody track indicating system may be installed on moving bodies such asships or airplanes. Hereinafter, the present invention will be describedwith reference to a ship track indicating system although, as explainedabove, the invention is not limited to that particular system.

Ship track indicating systems have been proposed and widely used inwhich a mechanically operated X-Y recorder successively plots thepositions of a ship on a chart based on positional information suppliedfrom a navigational aid device thereby tracing the ship's track on thechart. The X-Y recorder in these systems is operated in such a way thatthe recording pen thereof is moved in X and Y directions throughdistances determined both by the distance difference between a referencepoint and the ship's position and by the scale of the chart used. Inoperation, complicated adjustments must firstly manually be made toestablish a reference point on the chart and to determine the amount ofmovement of the recording pen in accordance with the map scale selected.Further, when a magnified or reduced pattern of the ship's track isdesired to be recorded on the recording paper, the amount of travel ofthe recording pen must be manually re-adjusted. The conventional systemhas another drawback in that the pattern of the recorded ship's tracktogether with the longitude and latitude line markers cannot be shiftedto a desired position. If a shift were to be attempted, the same patternwould simply be reproduced at a different position on the recordingpaper even if the reference point is moved to a proper position.Furthermore, the reference point must be manually re-adjusted when theposition of a ship goes beyond the boundary of the chart making itnecessary to always begin plotting the position of the ship at anappropriate part of the recording paper.

Accordingly, an object of the invention is to provide a ship trackindicating system which can electronically automatically indicate on thedisplay surface of an indicator longitude and latitude line markers aswell as a ship's track.

Another object of this invention is to provide a ship track indicatingsystem which can automatically magnify or reduce the displayed patternover the indicating surface of an indicator.

Yet another object of this invention is to provide a ship trackindicating system which can automatically shift the displayed pattern toany desired position over the indicating surface of an indicator.

Still another object of this invention is to provide a ship trackindicating system which can indicate movable cursor line markers whichare parallel to the longitude and latitude line markers in addition tothe ship's track with the longitude and latitude line markers extendingover the display surface of an indicator.

A still further object of this invention is to provide a ship trackindicating system which can indicate symbols corresponding to the cursorline markers parallel to the latitude and longitude line markers.

Moreover, an object of this invention is to provide a ship trackindicating system which can automatically magnify or reduce thedisplayed pattern wherein the ship's track, the longitude and latitudeline markers, and the cursor line markers and/or the symbols associatedtherewith are displayed.

A further object of this invention is to provide a a ship's trackindicating system which can automatically shift the displayed pattern toa desired position wherein the ship's track, the longitude and latitudeline markers, and the cursor line markers and/or the symbols associatedtherewith are displayed.

Another object of this invention is to provide a ship track indicatingsystem which can automatically shift the displayed pattern to a properposition wherein the ship's track as well as the longitude and latitudeline markers, the cursor line markers and associated symbols are stillindicated when the present position of a ship goes beyond the displaysurface of the indicator.

One more object of this invention is to provide a moving body trackindicating system which can electronically automatically indicate on theindicating surface of an indicator longitude and latitude line markersas well as a moving body's track.

SUMMARY OF THE INVENTION

In order to achieve these and other object of the invention, inaccordance with one aspect of the present invention, a moving body trackindicating system is provided which includes (i) indicating means forindicating on an indicating surface thereof the track of a moving bodyand longitude line and latitude line markers, (ii) storing means forstoring electrical signals corresponding to each of the moving body'strack and the longitude and latitude line markers, (iii) controllingmeans for reading from the storing means and supplying the electricalsignals to the indicating means, (iv) first signal generating means forgenerating the signals corresponding to the moving body's position inresponse to information supplied from means for measuring the positionof the moving body, (v) second signal generating means for generatingthe signals corresponding to the longitude and latitude line markers inresponse to information supplied from the means for measuring theposition of the moving body, and (vi) writing means for writingelectrical signals produced in response to the signals from the firstand second signal generating means into the storing means.

Other objects and features of the present invention will be described inmore detail herein with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphic representation of the face of a cathode-ray tubeused in a ship track indicating system constructed in accordance with apreferred embodiment of the present invention;

FIG. 2 is a general schematic block diagram of a ship track indicatingsystem constructed in accordance with the preferred embodiment of theinvention;

FIG. 3 is a general schematic block diagram of a ship track indicatingsystem constructed in accordance with a second embodiment of theinvention;

FIG. 4 is a detailed schematic block diagram of the ship trackindicating system of FIG. 3;

FIG. 5 is a detailed schematic block diagram of the longitude andlatitude line marker indicating section of the ship track indicatingsystem illustrated in FIG. 4;

FIG. 6 is a detailed schematic block diagram of the ship's positionplotting section of the ship track indicating system illustrated in FIG.4;

FIG. 7 is a detailed schematic block diagram combining the diagrams ofFIGS. 5 and 6;

FIG. 8 is a detailed schematic block diagram of the cursor line markersindicating section of the ship track indicating system illustrated inFIG. 4;

FIG. 9 is a detailed schematic block diagram of the longitude signalgenerator or latitude signal generator of the ship track indicatingsystem illustrated in FIGS. 4, 5 or 7;

FIG. 10 is a schematic block diagram of the ship position signalgenerator of ship track indicating system illustrated in FIGS. 4, 6 or7;

FIG. 11 is a schematic block diagram of the NV-LL transformer of theship track indicating system illustrated in FIGS. 4 or 8; and

FIG. 12 is a schematic block diagram of an automatic pattern shifterused with the ship track indicating system according to the presentinvention.

Throughout the drawings, the same reference numerals are given to likecomponents and the same alphabetic reference designations are given tolike signals.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIG. 1, the plotted track of a ship 1, longitude linemarkers 2, latitude line markers 3, cursor line markers 4, and symbols 5and 6 which identify by longitude and latitude the respective cursorline markers are indicated upon the face 7 of a cathode-ray tube.

Referring to FIG. 2, longitude line markers 2, latitude line markers 3and the track of a ship 1 are indicated upon the face 7 of a cathode-raytube (CRT). A display memory unit 8 stores electrical signalscorresponding to each of the ship's tracks and the longitude andlatitude line markers. A read control circuit 9 appropriately controlsthe display memory unit 8 and the CRT so that the electrical signalsread from the memory unit 8 produce bright spots at corresponding placesupon the face 7 of the CRT so as to indicate the ship's track as well asthe line markers. A ship position signal generator 10 generates inresponse to the information supplied from a navigational aid device 11signals corresponding to the position of the ship indicated upon theface 7 of the CRT. Markers signal generator 12 produces signalscorresponding to the longitude and latitude line markers displayed. Awrite control circuit 13 appropriately controls the ship position signalgenerator 10, the markers signal generator 12, and the display memoryunit 8 so that the electrical signals corresponding to the ship's trackand the longitude and latitude line markers are written intocorresponding selected locations of the display memory unit 8. Thenavigational aid device 11, which may for example include a Loranreceiver, produces the information corresponding to the instantaneousship's position.

As shown in the embodiment of FIG. 3, the navigational aid apparatus 20may be a Loran C receiver which produces at predetermined time intervalsinformation relating to the ship's position and transfers it to atransforming circuit 21. The transforming circuit 21 produces, inresponse to the position information transmitted from the navigationalaid device 20, numerical value signals indicating the longitude andlatitude of the ship's position which are coupled to a line markerssignal generator 14 and a ship position memory unit 34. The line markerssignal generator 14 produces the signals corresponding to the longitudeand latitude line markers which are displayed upon the face of the CRT.The ship position memory unit 34 passes pairs of the longitude andlatitude numerical value signals to a ship position signal generator 35while also successively storing the pairs of signals therein. The shipposition signal generator 35 produces the signals corresponding to theship's position indicated upon the face of the CRT. The write controlcircuit 13 appropriately controls the line markers signal generator 14,the ship position signal generator 35 and the display memory unit 8 sothat electrical signals corresponding to the ship's track and thelongitude and latitude line markers are written, in response to theoutput signals from the signal generators 14 and 35, into properlocations in the display memory unit 8. The read control circuit 9controls the display memory unit 8 and the indicator so as to therebydisplay the ship's track and the longitude and latitude line markersupon the face 7 of the CRT.

Referring to FIG. 5, the operation of displaying longitude and latitudeline markers upon the face of the CRT will first be explained. Longitudeline markers 2 and latitude line markers 3 are both displayed upon theface 7 of the CRT. A scanning circuit 15 is controlled by a read controlcircuit 16 to scan the electron beam of the CRT in both horizontal andvertical directions. The read control circuit 16 appropriately controlsthe display memory unit 8, a memory buffer register 17 and the scanningcircuit 15 so that the digital electrical signals read from the displaymemory unit 8 are transmitted through the memory buffer register 17 tothe intensity modulation input of the CRT so as to thereby display thelongitude and latitude line markers upon the face thereof. The displaymemory unit 8 includes, by way of example, m×n semiconductor RAM (randomaccess memory) elements arranged in m columns and n rows with the numberof RAM elements being the same as that of the picture elements of thescreen of the CRT wherein the picture elements may also be arranged in mcolumns and n rows. The display memory unit 8 writes a 1 into thestorage location determined by the address lines supplied from the X-and Y-address registers 18 and 19 while all other storage elements aremaintained in a 0 state. The display memory unit 8 simultaneously readsout all the signals in a given row thereof and loads them in parallelinto the memory buffer register 17. The memory buffer register 17,controlled by the read control circuit 16, serially reads out the storedsignals coupling them to the intensity modulation input of thecathode-ray tube.

The transforming circuit 21 produces, in response to the ship positioninformation transmitted from the radio navigational aid device 20, thenumerical value signals indicating the longitude and latitude of theship's position which are coupled to up-down counters 22 and 23. Theup-down counters 22 and 23 respectively set therein the longitude andlatitude numerical value signals corresponding to a reference point, byway of example, fixed at the center of the face of the CRT. The up-downcounter 22 initially sets therein, by way of example, a first longitudenumerical value signal representative of the ship's position soon afterthe ship track indicating system is connected to power mains andthereafter continuously supplies the signal to a longitudinal signalgenerator 25. The up-down counter 23 sets therein the first latitudenumerical value signal representative of the ship's position andcontinuously supplies the signal to a latitude signal generator 26. Thelongitude signal generator 25 produces the numerical value signalscorresponding to the longitude line markers displayed upon the face ofthe CRT supplying them to the X-address register 18 through an OR gate27 and also transmits a driving pulse to a counter 28 to enable it tosuccessively supply a series of increasing numerical values to theY-address register 19 through an OR gate 29. The X- and Y-addressregisters 18 and 19 are respectively provided with m and n elements andcorresponding select address lines of the display memory unit 8 whenparticular register elements thereof are identified. Some elements ofthe X-address register 18 are fixedly identified by the output signalsfrom the longitude signal generator 25 and each of the elements of theY-address register 19 is successively identified thereby writing 1'sinto all the storage elements in the columns selected by the X-addressregister 18 and hence storing all the necessary signals to display thelongitude line markers.

The latitude signal generator 26 produces the numerical value signalsrespectively corresponding to the latitude line markers indicated uponthe face of the CRT and couples them to the Y-address register 19through an OR gate 29. The latitude signal generator 26 also transmits adriving pulse to a counter 30 to enable it to successively supply aseries of increasing numerical values to the X-address register 18through an OR gate 27. In the same manner as in the case of longitudeline markers, some elements of the Y-address register 19 are fixedlyidentified by the output signals from the latitude signal generator 26and each of the elements of the X-address register 18 is successivelyidentified thereby writing 1's into all the storage elements in the rowsselected by the Y-address register 19 and hence storing all thenecessary signals required to display latitude line markers on the faceof the CRT. The construction and operation of the longitude and latitudesignal generators 25 and 26 will be explained later in further detail.

A magnifying ratio setting unit 31 produces signals utilized formagnifying or reducing the pattern displayed upon the face of the CRT toeach of the longitude and latitude signal generators 25, 26. Themagnifying ratio setting unit 31 comprises an up-down counter whichproduces numerical values to the signal generators 25, 26, and iscontrolled by a magnifying ratio selector switch 32 through an interfaceunit 33.

When it is desired to magnify or reduce the pattern displayed upon theface of the CRT, the magnifying ratio selector switch 32 is depressed tocause the interface unit 33 to transmit a reset pulse to the displaymemory unit 8 and to cause the magnifying rate setting unit 31 totransmit signals to the longitude and latitude signal generators 25 and26. The reset pulse first clears all the electrical digital signalsstored in the display memory unit 8. The longitude and latitude signalgenerators 25 and 26 then produce the numerical value signalsrespectively corresponding to the longitude and latitude line markers tobe displayed at a magnified scale upon the face of the CRT. Accordingly,the electrical digital signals corresponding to the longitude andlatitude line markers on a magnified scale are stored in the displaymemory unit 8 as a result of which magnified longitude and latitude linemarkers are plotted upon the face of the CRT.

Referring to FIG. 6, the operation of plotting the track of a ship uponthe face of the CRT will be explained. The transforming circuit 21produces the numerical value signals corresponding to the longitude andlatitude of the ship's position which are coupled to the up-downcounters 22 and 23 and the ship position memory unit 34. The up-downcounters 22 and 23 respectively set therein the longitude and latitudesignals of the reference point, which is the center of the face 7 of theCRT, and continuously supply them to a ship position signal generator36. The ship position memory unit 34, which may be constructed ofsemiconductor RAM elements and is controlled by a write control circuit39, passes a pair of the longitude and latitude numerical value signalsto the ship position signal generator 36 and at the same time stores thesignals representative of the ship's position accumulatively. The writecontrol circuit 39 comprises a counter which repetitiously performs anincreasing count operation from one to the same number of the memoryelements of the ship position memory unit 34, and produces countedvalues to locate the memory elements into which the signals from thetransforming circuit 21 are written. The ship position signal generator36 includes longitude and latitude units 37 and 38. The longitude unit37 produces a numerical value signal corresponding to positions of theship displayed upon the face of the CRT in response to the outputsignals received from the up-down counter 22 and the ship positionmemory unit 34 and couples the numerical value signal to the X-addressregister 18. The latitude unit 38 supplies a numerical value signalcorresponding to the positions of the ship upon the display surface inresponse to the output signals received from the up-down counter 23 andthe ship position memory unit 34 and couples that numerical value signalto the Y-address register 19. The construction and operation of thelongitude and latitude units 37, 38 will be explained in detail later.The X- and Y-address registers 18 and 19 respectively selectcorresponding imaginary address lines corresponding to a selectedlocation thereby writing a 1 into the selected storage location of thedisplay memory unit 8.

This operation is repeated every time the output signals from the shipposition memory unit 34 are produced with the result that correspondingelectrical digital signals relating to the ship's track are stored inthe display memory unit 8. The read control circuit 16 appropriatelycontrols the display memory unit 8, the memory buffer register 17 andthe scanning circuit 15 so that the ship's track is plotted upon theface of the CRT. The output signals from the magnifying rate settingunit 31 are supplied to the ship position signal generator 36.

When it is desired to magnify or reduce the pattern displayed upon theface of the CRT, the magnifying switch 32 is depressed causing theinterface unit 33 to transmit pulse signals to the display memory unit 8and a read control circuit 40. The read control circuit 40 comprises acounter produces counted values to locate the memory elements of theship position memory unit 34 from which the stored signals are read out.The pulse applied to the display memory unit 8 first clears all theelectrical digital signals previously stored therein. Then, the readcontrol circuit 40 is made to successively transmit the stored longitudeand latitude signals one after another to the ship position signalgenerator 36. Accordingly, electrical digital signals corresponding tothe ship's track on a magnified scale are stored in the display memoryunit 8 as a result of which a magnified ship's track is plotted upon theface 7 of the CRT.

The ship's track together with the longitude and latitude line markersare displayed upon the face of the CRT and the displayed pattern thereofcan be magnified or reduced by means of the magnifying switch 32 withthe circuit shown in FIG. 7 in which the circuits illustrated in FIGS. 5and 6 have been combined.

Referring to FIG. 9, the construction and operation of the longitudesignal generator 25 will be explained. A reference marker signalgenerating unit 45 produces a signal representing the longitude of areference longitude line marker positioned close to a reference point,for example, the center of the display surface of the CRT. A face edgesignal generating unit 46 produces a signal representing the longitudeof the left-hand edge of the display surface which a line marker signalgenerating unit 47 produces signals representing each of the longitudesof the longitude line markers displayed upon the face of the CRT. Asubtractor 48 produces longitude differences signal by successivelysubtracting each of the longitudes of the longitude line markers fromthat of the reference point. A divider 49 divides each of the longitudedifferences by a numerical value in accordance with the selected scaleof the pattern displayed upon the face of the CRT thereby successivelyproducing signals corresponding to each of the longitude line markerswith these signals being coupled to the X-address register 18.

The reference marker signal generating unit 45 is constructed of asetting unit 51, a divider 52 and a multiplier 53. The setting unit 51produces a longitude difference signal representing the longitudedifference between two adjacent longitude line markers displayed uponthe face of the CRT with the longitude difference signal being coupledto inputs of the divider 52 and the multiplier 53. The divider 52divides the longitude of the reference point signal, which is suppliedto the other input, by the longitude difference signal and couples apredetermined number of bits of the quotient to the multiplier 53 withthe remainder truncated. The multiplier 53 multiplies the quotient bythe longitude difference signal thereby producing the longitude of thereference longitude line marker.

The face edge signal generating unit 46 is constructed of a setting unit54, a multiplier 55 and a subtractor 56. The setting unit 54 transmitssignal N representing half the width of the face of the CRT to one inputof the multiplier 55. The multiplier 55 multiplies the distance of thewidth by the numerical value supplied to the other input in accordancewith the selected scale. The subtractor 56 subtracts the output signalfrom the multiplier from the signal E representing the longitude of thereference point supplied thereto thereby producing a signal representingthe longitude of the edge of the face of the CRT.

The line markers signal generating unit 47 includes a subtractor 57, acomparator 58, an accumulator 59 and a gate 90. The subtractor 57subtracts the output signal from the accumulator 59 from the longitudeof the reference longitude line marker transmitted by the unit 45, andtransmits its output signal Z to one inputs of the comparator 58 and thegate 90. The comparator 58 compares the output signal Z from thesubtractor 57 and the signal E from the face edge signal generating unit46, and transmits an output signal to the accumulator 59 and to thecontrol input of the gate 90 when the relationship between the inputsignals is E<Z. The accumulator adds to a previously accumulated valuestored therein a signal representing the longitude difference betweentwo adjacent longitude line markers each time the signal is received,the accumulated value being initially zero, and transmits the sum to thesubtractor 57. The gate 90 passes the signal Z, when the signal isapplied to the control input thereof, to one input of the subtractor 48.The subtractor 48 successively subtracts each of the longitudes of thelongitude line markers supplied to one input thereof from the longitudeof the reference point supplied to the other input. The divider 49divides each of the longitude differences from the subtractor 48 by thenumerical value transmitted thereto by the magnifying rate setting unit31 thereby successively producing the signals corresponding to thelongitude line markers displayed to the left of the reference point uponthe face of the CRT.

Similarly, the signals corresponding to the longitude line markersdisplayed to the right of the reference point upon the face of the CRTcan also be obtained by a minor modification of the schematic blockdiagram illustrated in FIG. 9. To do this, the subtractor 56 of the faceedge signal generating unit 46 is to be replaced by an adder with itstwo input terminals connected to receive the output signals from themultiplier 55 and the longitude of the reference point. The subtractor57 of the line markers signal generating unit 47 is to be replaced by anadder which adds the output signals from the reference marker signalgenerating unit 45 and the adder 59 to one another. The comparator 58should pass the signal Z and produce a driving pulse to the adder 59when the relationship therebetween is E>Z.

In substantially the same manner, the signals corresponding to thelatitude line markers displayed upon the face of the CRT can beobtained.

Referring to FIG. 9, in order to obtain the signals corresponding to thelatitude line markers displayed to the lower side of the reference pointupon the display surface, the latitude of the reference point is to beapplied to one input of the divider 52, the subtractor 56 and thesubtractor 48. Secondly, the setting unit 51 is to be connected so as toproduce a latitude difference between two adjacent latitude line markersdisplayed upon the face of the CRT. Finally, the setting unit 54 is tobe designed to output a signal representing half the height of thedisplay surface of the indicator.

Further, in order to obtain the signals corresponding to the latitudeline markers displayed to the upper side of the reference point upon theface of the CRT, referring to FIG. 9, first the subtractor 56 is to bereplaced by an adder. Secondly, the subtractor 57 is to be replaced byan adder, and, thridly, the comparator 58 is to pass the signal Z andproduce a driving pulse to the adder 59 when the mutual relationship isE>Z.

Referring to FIG. 10, the construction and operation of the shipposition signal generator 36 will be explained. The longitude of thereference point signal supplied from the up-down counter 22 is appliedto one input of a subtractor 61 and the latitude of the reference pointsupplied from the up-down counter 23 is applied to one input of asubtractor 62. The longitude and latitude signals representing thepresent ship's position are respectively supplied to the other inputs ofthe subtractors 61 and 62 from the ship position memory unit 34. Thesubtractor 61 subtracts, by way of example, the longitude of thereference point from the longitude of the present ship's position andproduces in response thereto a difference signal which is sent to adivider 63. The divider 63 divides the supplied difference signal by anumerical value transmitted thereto from the magnifying ratio settingunit 31 thereby producing the signal corresponding to the ship'sposition displayed upon the face of the CRT. The subtractor 62 subtractsthe latitude of the reference point from the latitude of the presentship's position and produces therefrom a difference signal which iscoupled to a divider 64. The divider 64 divides the supplied differencesignal by the numerical value applied thereto by the magnifying ratiosetting unit 31 thereby producing the signal corresponding to the ship'sposition.

Referring to FIG. 7, the operation of moving the displayed pattern to adesired position upon the face of the CRT will be explained. Thedisplayed pattern includes the ship's track and the longitude andlatitude line markers.

A pattern moving switch 66 and an interface unit 67 are added to thecombination of the schematic diagrams of FIGS. 5 and 6. The patternmoving switch 66 includes four switch elements 66l, 66r, 66u and 66d.The interface unit 67 supplies control signals to the control input ofthe up-down counter 22 when either one of the switch elements 66l or 66ris depressed and to the control input of the up-down counter 23 wheneither one of the switch elements 66u or 66d is depressed. The up-downcounter 22 performs an incrementing operation when the switch element66r is depressed so that the longitude numerical value of the referencepoint is increased while the latitude numerical value thereof is heldconstant. Conversely, when the switch element 66l is depressed, theup-down counter 22 performs a decrementing operation so that thelongitude numerical value of the reference point is decreased.Similarly, the up-down counter 23 increments the latitude numericalvalue of the reference point when the switch element 66u is depressedand decrements the latitude numerical value of the reference point whenthe switch element 66d is depressed. The interface unit 67 transmits areset pulse to the display memory unit 8 to clear the electrical signalsstored in the memory unit 8 and a start pulse to the ship positionmemory unit at the moment the depressed switch is restored therebystarting the successive transmission of the stored signals one afteranother to the ship position signal generator 36.

Accordingly, the displayed pattern moves to the right when the switchelement 66r is depressed and moves to the left when the element 66l isdepressed. Similarly, the displayed pattern moves upwards when theswitch element 66u is depressed and moves at a predetermined angle of45° with respect to the horizontal when the switch elements 66r and 66uare simultaneously depressed.

Referring next to FIG. 8, the operation of the indicating cursor linemarkers upon the face of the CRT will be explained. A cursor markerswitch 69 is made up of four switch elements 69l, 69r, 69u and 69d. Aninterface unit 70 supplies control signals to the control input of anup-down counter 71 when either one of the switch elements 69l or 69r isdepressed and to the control input of an up-down counter 72 when eitherone of the switch elements 69u or 69d is depressed. The up-down counter71 performs an incrementing operation when the switch element 69r isdepressed so that an appropriate numerical value is transmitted to anNV-LL transformer 73 and to the X-address register 18 through the ORgate 27. The counter 71 performs a decrementing operation when theswitch element 69l is depressed. The interface unit 70 transmits adriving pulse to a counter 74 and a gate controller 75 at the momentwhen one of the depressed switch elements 69l and 69r is restored. Thecounter 74 successively produces increasing numerical values which aresent to a gate 76 and to one input of the gate controller 75. The gatecontroller 75 causes the gate 76 to intermittently pass the outputsignals from the counter 74 to the Y-address register 19. The gatecontroller 75 comprises a counter which is put into operation by thedriving pulse from the unit 70 and senses to count the change of thecounted value produced by the counter 74 and produces a control signalto the control input of the gate 76, every time it counts the change upto a predetermined number, for example up to three, thereby closing thegate 76 for a period and hence causing it to intermittently pass theoutput signal from the counter 74.

Elements of the X-address register 18 are identified by the numericalvalues supplied thereto by the up-down counter 71. The elements of theY-address register 19 are successively intermittently identified everypredetermined number of elements thereof by the output signals from thecounter 74. Accordingly, the display memory unit 8 writes 1's into thestorage elements in the column selected by the X-address register 18thereby storing the necessary signals to display a dotted cursor linemarker parallel to the longitude line markers.

Similarly, the up-down counter 72 performs an incrementing or adecrementing operation when a corresponding one of the switch elements69u and 69d is depressed so that a numerical value is transmitted to theNV-LL transformer 73 and also to the Y-address register 19 through theOR gate 29. The interface unit 70 transmits a driving pulse to a counter77 and a gate controller 78 at the moment when one of the depressedswitch elements 69u and 69d is restored. In substantially the samemanner, a cursor line marker parallel to the latitude line markers canbe displayed at any desired position upon the face of the CRT as in thecase of displaying a cursor line marker parallel to the longitude linemarkers. The operation thereof is self-evident and hence need not berepeated here.

Next, the operation of displaying the symbols for cursor line markerswill be explained. The NV-LL transformer 73 produces, in response to theoutput signal from the up-down counter 71, a numerical valuecorresponding to the longitude of the cursor line marker displayed uponthe face of the CRT and couples it to a character generator 81. TheNV-LL transformer also produces, in response to the output signal fromthe up-down counter 72, a numerical value corresponding to the latitudeof a cursor line marker and couples it to the character generator 81.The character generator 81 successively produces numerical value signalswhich are coupled to the X- and Y-address registers respectively,thereby writing 1's into the storage elements selected by the registers18 and 19. The stored electrical signals are read from the displaymemory unit 8 and supplied to the indicator so that the symbolsindicating, for example, the longitude of a cursor line marker isdisplayed at a position close to the line marker such as the symbol 5illustrated in FIG. 1. The latitude symbol 6 for a cursor line marker 4is also indicated in the same manner.

Referring to FIG. 11, the NV-LL transformer 73 is constructed of amultiplier 83 and an adder 84. The multiplier 83 multiplies the outputsignal from the up-down counter 71 by the numerical value relating tothe selected scale of the displayed pattern supplied from the magnifyingrates setting unit 31. The adder 84 adds the product signal to thesignal representing the longitude of the left edge of the face of theCRT thereby producing a signal representing the longitude of a cursorline marker. Similarly, the latitude numerical value of a cursor linemarker is obtained by replacing the up-down counter 71 with the up-downcounter 72 and by supplying to the adder 84 the latitude of a lower edgeof the face of the CRT.

Referring to FIG. 4, a detailed schematic block diagram is shown whichcombines the schematic diagrams illustrated in FIGS. 7 and 8.

When it is desired to move the cursor line marker which is parallel tothe longitude line markers to the right direction, the switch element69r is depressed. The interface unit 70 then transmits a reset pulse tothe display memory unit 8 and a start pulse to the read control circuit40 at the moment when the depressed switch element is restored. Thedisplay memory unit 8 is first cleared, and then 1's are written intothe storage locations selected based on the output signals from theup-down counters 71, 72, the longitude and latitude signal generators25, 26, and the ship position memory unit 34. As a result, a cursor linemarker as well as the ship's track and the longitude and latitude linemarkers are displayed at a new positions.

When it is desired to magnify or reduce the displayed pattern whereinthe cursor line markers as well as the ship's track and the longitudeand latitude line markers are all simultaneously magnified or reduced,the magnifying switch 32 is depressed thereby moving the ship's trackand the longitude and latitude line markers to new positions. However,the cursor line markers continue to be displayed at the same positionswith the symbols indicating the longitude and latitude of the linemarkers changing with the magnification ratio of the displayed pattern.

When it is desired to move the displayed pattern, for example, to theright, the switching element 66r is depressed thereby moving the ship'strack and the longitude and latitude line markers to new positions butmaintaining the cursor line markers at the same positions. Moreover, thesymbols indicating the longitude and latitude of the cursor line markersalso change with movement of the displayed pattern.

Referring to FIG. 12, the construction and operation of an automaticpattern shifter will be explained. For the purpose of this explanation,it is assumed that the ship is moving to the left upon the face of theCRT. An automatic pattern shifter 85 includes a comparator 86 and acontrol signal generator 87 with an adjusting switch 88. The comparator86 compares the longitude of the ship's present position P supplied fromthe ship position memory unit 34 and the longitude E of the left-handedge of the face of the CRT supplied from the face edge signalgenerating unit 46 and produces in response thereto a driving pulsewhich is coupled to the control signal generator 87 when the mutualrelationship therebetween is E>P. The control signal generator 87produces control signals which are coupled to the up-down counter 22which in response thereto decrements its numerical value by apredetermined amount so that the present ship's position is moved to theright to a new position determined by the predetermined amount ofchange. The amount of decrement can be varied by the adjusting switch88.

Similarly, the displayed pattern can be automatically shifted in theopposite direction to the direction of movement of the ship when theship goes beyond the right-hand edge of the face of the indicator. Inthis case, the face edge signal generating unit 46 supplies thelongitude of the right-hand edge of the display surface and the controlsignal generator 87 causes the up-down counter 22 to increment itsnumerical value by a variable predetermined amount.

In the same manner, the displayed pattern can be automatically shiftedupwardly or downwardly when the ship goes beyond the lower or upper edgeof the face of the CRT. For this, a control signal from the controlsignal generator 87 is supplied to the up-down counter 23 and the faceedge generating unit 46 applies a signal representing the latitude ofthe lower or upper edge of the face.

It should be noted that the indicator used with the invention is notlimited to a CRT as used in the embodiments described above. For examplean array of light-emitting diodes, a plasma display or any of a numberof other display devices can also used instead.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made thereto withoutdeparting from the spirit and scope of the invention.

What is claimed is:
 1. A moving body track indicating system whichindicates the track of a moving body on the indicating surface of anindicator in response to information supplied from means for measuringthe position of the moving body comprising:(i) transforming means forproducing first and second signals respectively indicating the longitudeand the latitude of the position of the moving body in response to theinformation supplied from said means for measuring the position of themoving body; (ii) line markers signal generating means for producingsignals corresponding to longitude line and the latitude line markersbased on the first and second signals from said transforming means;(iii) first storing means for storing signals corresponding to each ofthe track of the moving body and the longitude and the latitude linemarkers; (iv) second storing means for storing the first and secondsignals from said transforming means; (v) body position signalgenerating means for generating signals corresponding to the positionmarks of the moving body constituting the track thereof in response tothe first and second signals from said second storing means; (vi)writing means for writing the signals produced in response to signalsfrom said body position signal generating means and from said linemarkers signal generating means into said first storing means; (vii)indicating means for displaying on said indicating surface the track ofthe moving body and the longitude line and the latitude line markers;and (viii) controlling means for reading signals from said first storingmeans and supplying them to said indicating means.
 2. A moving bodytrack indicating system as defined in claim 1 further comprising meansfor producing control signals in accordance with the scale of thepattern displayed upon said indicating surface, said body positionsignal generating means and said line markers signal generating meansbeing controlled by said control signal producing means.
 3. A movingbody track indicating system as defined in claim 1 wherein said bodyposition signal generating means comprises:(i) first body positionsignal generating means for generating said signals corresponding to themoving body's position in response to said first signal from saidtransforming means; and (ii) second body position signal generatingmeans for generating said signals corresponding to the moving body'sposition in response to said second signal from said transforming means.4. A moving body track indicating system as defined in claim 1 whereinsaid line markers signal generating means comprises:(i) reference pointstoring means for storing a pair of said first and second signals fromsaid transforming means; (ii) first line marker signal generating meansfor producing said signals corresponding to the longitude line markersin response to said first signal; and (iii) second line marker signalgenerating means for producing said signals corresponding to saidlatitude line markers in response to said second signal.
 5. A movingbody track indicating system as defined in claim 3 wherein said firstbody position signal generating means comprises:(i) reference pointstoring means for storing a pair of said first and second signals fromsaid storing means; (ii) subtracting means for performing a subtractionoperation between the first signal from said reference point storingmeans and the first signal from said transforming means; and (iii) meansfor operationally multiplying the output signals from said subtractingmeans by a numerical value determined in accordance with the scale ofthe pattern upon said indicating surface.
 6. A moving body trackindicating system as defined in claim 3 wherein said second bodyposition signal generating means comprises:(i) reference point storingmeans for storing a pair of said first and second signals from saidstoring means; (ii) subtracting means for performing a subtractionoperation between said second signal from said reference point storingmeans and said second signal from said transforming means; and (iii)means for operationally multiplying the output signals from saidsubtracting means by a numerical value determined in accordance with thescale of the pattern upon said indicating surface.
 7. A moving bodytrack indicating system as defined in claim 4 wherein said first linemarker signal generating means comprises:(i) longitude line signalgenerating means for producing the longitude numerical value of alongitude line marker positioned in the vicinity of a reference pointupon said indicating surface in response to said first signal from saidreference point storing means; (ii) means for operationally adding thedistance numerical value between two adjacent longitude line markersupon said indicating surface and the longitude numerical value from saidlongitude line signal generating means; and (iii) means foroperationally multiplying the output signals from said means foroperationally adding by a numerical value determined in accordance withthe scale of the pattern upon said indicating surface.
 8. A moving bodytract indicating system as defined in claim 4 wherein said second linemarker signal generating means comprises:(i) latitude line signalgenerating means for producing the latitude numerical value of alatitude line marker positioned in the vicinity of a reference pointupon said indicating surface of an indicator in response to said secondsignal from said reference point storing means; (ii) means foroperationally adding the distance numerical value between two adjacentlatitude line markers upon said indicating surface and the latitudenumerical value from said latitude line signal generating means; and(iii) means for operationally multiplying the output signals from saidmeans for operationally adding by a numerical value determined inaccordance with the scale of the pattern upon said indicating surface.9. A moving body track indicating system as defined in any of claims 5,6, 7 and 8 wherein the magnitudes of said first and second signals fromthe reference point storing means are separately variable.
 10. A movingbody track indicating system as defined in any of claims 5, 6, 7 and 8wherein said numerical value determined in accordance with the scale ofthe pattern upon said indicating surface is variable.
 11. A moving bodytrack indicating system as defined in any of claims 5, 6, 7 and 8further comprising:(i) means for detecting that the body's position hasreached the edge of said indicating surface; and (ii) means for varyingthe magnitudes of said first and second signals from said referencestoring means automatically in accordance with the output signals fromsaid detecting means.
 12. A moving body track indicating system whichindicates the track of a moving body on the indicating surface of anindicator in response to information supplied from means for measuringthe position of the moving body comprising:(i) transforming means forproducing first and second signals respectively indicating the longitudeand the latitude of the position of the moving body in response to theinformation supplied from said means for measuring the position of themoving body; (ii) line markers signals generating means for producingsignals corresponding to longitude and latitude line markers in responseto the first and second signals from said transforming means; (iii)cursor line markers signal generating means for producing signalscorresponding to cursor line markers parallel to the latitude and thelongitude line markers; (iv) first storing means for storing signalscorresponding to each of the track of the moving body, the longitudeline and the latitude line markers, and the cursor line markers; (v)writing means for writing signals produced in response to signals fromsaid body position signal generating means, said line markers signalgenerating means, and said cursor line markers signal generating meansinto said first storing means; (vi) second storing means for storing thefirst and second signals from said transforming means; (vii) bodyposition signal generating means for producing signals corresponding tothe position marks of the moving body constituting the track thereof inresponse to the first and second signals from said second storing means;(viii) indicating means for displaying on said indicating surface thetrack of the moving body, the longitude and the latitude line markers,and the cursor line markers, and; (ix) controlling means for readingsignals from said first storing means and supplying them to saidindicating means.
 13. A moving body track indicating systemcomprising:(i) means for measuring the position of a moving body; (ii)transforming means for producing first and second signals respectivelyindicating the longitude and the latitude of the position of the movingbody in response to information supplied from said means for measuringthe position of a moving body; (iii) line markers signal generatingmeans for producing said signals corresponding to the longitude line andlatitude line markers based on said first and second signals from saidtransforming means; (iv) first storing means for storing signalscorresponding to each of the track of the moving body and the longitudeand latitude line markers; (v) second storing means for storing saidfirst and second signals from said transforming means; (vi) bodyposition signal generating means for generating signals corresponding tothe position of the moving body in response to said first and secondsignals from said second storing means; (vii) writing means for writingsaid signals produced by said body position signal generating means andfrom said line markers signal generating means into said first storingmeans; (viii) indicating means for displaying on an indicating surfacethereof the track of the moving body and the longitude line and thelatitude line markers; and (ix) controlling means for reading signalsfrom said first storing means and supplying them to said indicatingmeans.
 14. A moving body track indicating system comprising:(i) meansfor measuring the position of a moving body; (ii) transforming means forproducing first and second signals respectively indicating the longitudeand the latitude of the position of the moving body in response toinformation supplied from said means for measuring the position of amoving body; (iii) line markers signal generating means for producingsignals corresponding to said longitude and latitude line markers inresponse to said first and second signals from said transforming means;(iv) cursor line markers signal generating means for producing signalscorresponding to cursor line markers parallel to said latitude and saidlongitude line markers; (v) first storing means for storing signalscorresponding to said position of the moving body, said longitude andlatitude line markers, and said cursor line markers; (vi) writing meansfor writing said signals produced by said body position signalgenerating means, said line markers signal generating means, and saidcursor line markers signal generating means directly into said firststoring means; (vii) second storing means for storing said first andsecond signals from said transforming means; (viii) body position signalgenerating means for producing said signals corresponding to theposition of the moving body in response to said first and second signalsfrom said second storing means; (ix) indicating means for displaying onan indicating surface thereof the track of the position of the movingbody, the longitude and the latitude line markers, and the cursor linemarkers; and (x) controlling means for reading from said first storingmeans and supplying said signals to said indicating means.
 15. A movingbody track indicating system which indicates the track of a moving bodyon the indicating surface of an indicator in response to informationsupplied from means for measuring the position of the moving body,comprising:(i) transforming means for producing first and second signalsrespectively indicating the longitude and latitude of the position ofthe moving body in response to the information supplied from said meansfor measuring the position of the moving body; (ii) body position signalgenerating means for producing signals corresponding to a position markof the moving body in response to the first and second signals from saidtransforming means; (iii) line markers signal generating means forproducing signals corresponding to longitude line and latitude linemarkers in response to the first and second signals from saidtransforming means, said line markers signal generating meanscomprising:(a) reference point storing means for storing a pair of thefirst and second signals from the transforming means; (b) first linemarker signal generating means for producing the signals correspondingto the longitude line markers in response to the first signalcomprising: (1) longitude line signal generating means for producing thelongitude numerical value of the longitude line marker in the vicinityof a reference point upon said indicating surface; (2) means foroperationally adding a distance numerical value between the adjacentlongitude line markers upon said indicating surface and the longitudenumerical value from said longitude line signal generating means; and(3) means for operationally multiplying the output signals from saidmeans for operationally adding by a numerical value determined inaccordance with the scale of the pattern upon said indicating surface;(c) second line maker signal generating means for producing the signalscorresponding to the latitude line markers in response to the secondsignal; (iv) storing means for storing signals corresponding to theposition marks of the moving body constituting the track thereof and thelongitude and latitude line markers; (v) writing means for writing thesignals produced in response to signals from said body position signalgenerating means and said line markers signal generating means into saidstoring means; (vi) indicating means for indicating on said indicatingsurface the track of the moving body and the longitude line and thelatitude line markers; and (vii) controlling means for reading signalsfrom said storing means and supplying them to said indicating means. 16.A moving body track indicating system which indicates the track of amoving body on the indicating surface of an indicator in response toinformation supplied from means for measuring the position of the movingbody, comprising:(i) transforming means for producing first and secondsignals respectively indicating the longitude and latitude of theposition of the moving body in response to the information supplied fromthe said means for measuring the position of the moving body; (ii) bodyposition signal generating means for producing signals corresponding toa position mark of the moving body in response to the first and secondsignals from said transforming means; (iii) line marker signalgenerating means for producing signals corresponding to longitude lineand latitude line markers in response to the first and second signalsfrom said transforming means, said line markers signal generating meanscomprising:(a) reference point storing means for storing a pair of thefirst and second signals from the transforming means; (b) first linemarkers signal generating means for producing the signals correspondingto the longitude line markers in response to the first signal; and (c)second line markers signal generating means for producing the signalscorresponding to the latitude line markers in response to the secondsignal, said second line markers signal generating means comprising: (1)latitude line signal generating means for producing the latitudenumerical value of sid latitude line maker in the vicinity of referencepoint upon said indicating surface; (2) means for operationally addingthe distance numerical value between two adjacent latitude line markersupon said indicating surface and the latitude numerical value from saidlatitude line signal generating means; and (3) means for operationallymultiplying the output signals from said means for operationally addingby a numerical value determine in accordance with the scale of thepattern upon said indicating surface; (iv) storing means for storingsignals corresponding to the position marks of the moving bodyconstituting the track thereof and the longitude and latitude linemarkers; (v) writing means for writing the signals produced in responseto signals from said body position signal generating means and said linemarkers signal generating means into said storing means; (vi) indicatingmeans for indicating on said indicating surface the track of the movingbody and the longitude line and the latitude line markers; and (vii)controlling means for reading signals from said storing means andsupplying them to said indicating means. .Iadd.
 17. A moving body trackindicating system comprising:(i) means for measuring the position of amoving body and producing first and second signals representative ofsaid position; (ii) line markers signal generating means for producingsignals corresponding to longitude line and latitude line markers basedon said first and second signals from said means for measuring theposition of a moving body; (iii) first storing means for storing signalscorresponding to each of the track of the moving body and the longitudeand latitude line markers; (iv) second storing means for storing saidfirst and second signals from said means for measuring the position ofthe moving body; (v) body position signal generating means forgenerating signals corresponding to the position of the moving body inresponse to said first and second signals from said second storingmeans; (vi) writing means for writing said signals produced by said bodyposition signal generating means and from said line markers signalsgenerating means into said first storing means; (vii) indicating meansfor displaying on an indicating surface thereof the track of the movingbody and the longitude line and the latitude line markers; and (viii)controlling means for reading said signals from said first storing meansand supplying them to said indicating means. .Iaddend. .Iadd.18. Amoving body track indicating system comprising: (i) means for measuringthe position of a moving body and producing first and second signalsrepresentative of said position; (ii) line markers signal generatingmeans for producing signals corresponding to longitude line and latitudeline markers based on said first and second signals from said means formeasuring the position of a moving body; (iii) first storing means forstoring signals corresponding to the track of the moving body; (iv)second storing means for storing said first and second signals from saidmeans for measuring the position of the moving body; (v) body positionsignal generating means for generating signals corresponding to theposition of the moving body in response to said first and second signalsfrom said second storing means; (vi) writing means for writing saidsignals produced by said body position signal generating means into saidfirst storing means; (vii) indicating means for displaying on anindicating surface thereof the track of the moving body and thelongitude line and the latitude line markers; and (viii) controllingmeans for reading said signals from said first storing means andsupplying them to said indicating means. .Iaddend. .Iadd.19. A movingbody track indicating system comprising:(i) means for providing firstand second signals representative of a position of a moving body; (ii)line markers signal generating means for producing signals correspondingto longitude line and latitude line markers based on said first andsecond signals; (iii) first storing means for storing signalscorresponding to each of the track of the moving body and the longitudeand latitude line markers; (iv) second storing means for storing saidfirst and second signals; (v) body position signal generating means forgenerating signals corresponding to the position of the moving body inresponse to said first and second signals from said second storingmeans; (vi) writing means for writing said signals produced by said bodyposition signal generating means and from said line markers signalsgenerating means into said first storing means; (vii) indicating meansfor displaying on an indicating surface thereof the track of the movingbody and the longitude line and the latitude line markers; and (viii)controlling means for reading said signals from said first storing meansand supplying them to said indicating means. .Iaddend. .Iadd.20. Amoving body track indicating system comprising:(i) means for measuringthe position of a moving body and producing first and second signalsrepresentative of said position; (ii) means for providing a pair offirst and second reference point signals related to said position of amoving body; (iii) line markers signal generating means for producingsignals corresponding to longitude line and latitude line markers basedon said first and second reference point signals; (iv) first storingmeans for storing signals corresponding to each of the track of themoving body and the longitude and latitude line markers; (v) secondstoring means for storing said first and second signals; (vi) bodyposition signal generating means for generating signals corresponding tothe position of the moving body based on said first and second signalsfrom said second storing means and said first and second reference pointsignals; (vii) writing means for writing said signals produced by saidbody position signal generating means and from said line markers signalsgenerating means into said first storing means; (viii) indicating meansfor displaying on an indicating surface thereof the track of the movingbody and the longitude line and the latitude line markers; and (ix)controlling means for reading said signals from said first storing meansand supplying them to said indicating means. .Iaddend. .Iadd.21. Amoving body track indicating system comprising: (i) means for measuringthe position of a moving body and producing first and second signalsrepresentative of said position; (ii) means for generating and storing apair of first and second reference point signals; (iii) line markerssignal generating means for producing signals corresponding to longitudeline and latitude line markers based on said first and second referencepoint signals from said reference point storing means; (iv) firststoring means for storing signals corresponding to each of the track ofthe moving body and the longitude and latitude line markers; (v) secondstoring means for storing said first and second signals; (vi) bodyposition signal generating means for generating signals corresponding tothe position of the moving body based on said first and second signalsfrom said second storing means and said first and second reference pointsignals from said reference point storing means; (vii) writing means forwriting said signals produced by said body position signal generatingmeans and from said line markers signals generating means into saidfirst storing means; (viii) indicating means for displaying on anindicating surface thereof the track of the moving body and thelongitude line and the latitude line markers; and (ix) controlling meansfor reading said signals from said first storing means and supplyingthem to said indicating means. .Iaddend. .Iadd.22. A moving body trackindicating system comprising:(i) means for providing first and secondsignals representative of a position of a moving body; (ii) line markerssignal generating means for producing signals corresponding to longitudeline and latitude line markers based on said first and second signals;(iii) first storing means for storing signals corresponding to the trackof the moving body; (iv) second storing means for storing said first andsecond signals; (v) body position signal generating means for generatingsignals corresponding to the position of the moving body in response tosaid first and second signals from said second storing means; (vi)writing means for writing said signals produced by said body positionsignal generating means into said first storing means; (vii) indicatingmeans for displaying on an indicating surface thereof the track of themoving body and the longitude line and the latitude line markers; and(viii) controlling means for reading said signals from said firststoring means and supplying them to said indicating means. .Iaddend..Iadd.23. A moving body track indicating system comprising: (i) meansfor measuring the position of a moving body and producing first andsecond signals representative of said position; (ii) means for providinga pair of first and second reference point signals related to a positionof said moving body; (iii) line markers signal generating means forproducing signals corresponding to longitude line and latitude linemarkers based on said first and second reference point signals; (iv)first storing means for storing signals corresponding to the track ofthe moving body; (v) second storing means for storing said first andsecond signals; (vi) body position signal generating means forgenerating signals corresponding to the position of the moving bodybased on said first and second signals from said second storing meansand said first and second reference point signals; (vii) writing meansfor writing said signals produced by said body position signalgenerating means into said first storing means; (viii) indicating meansfor displaying on an indicating surface thereof the track of the movingbody and the longitude line and the latitude line markers; and (ix)controlling means for reading said signals from said first storing meansand supplying them to said indicating means. .Iaddend. .Iadd.24. Amoving body track indicating system comprising: (i) means for measuringthe position of a moving body and producing first and second signalsrepresentative of said position; (ii) means for generating and storing apair of first and second reference point signals; (iii) line markerssignal generating means for producing signals corresponding to longitudeline and latitude line markers based on said first and second referencepoint signals from said reference point storing means; (iv) firststoring means for storing signals corresponding to the track of themoving body; (v) second storing means for storing said first and secondsignals; (vi) body position signal generating means for generatingsignals corresponding to the position of the moving body based on saidfirst and second signals from said second storing means and said firstand second reference point signals from said reference point storingmeans; (vii) writing means for writing said signals produced by saidbody position signal generating means into said first storing means;(viii) indicating means for displaying on an indicating surface thereofthe track of the moving body and the longitude line and the latitudeline markers; and (ix) controlling means for reading said signals fromsaid first storing means and supplying them to said indicating means..Iaddend.